Safety device for generators



March 12, 1940. E. HILLS 2,193,172

SAFETY DEVICE FOR GENERATORS Filed July 11, 1939 2 Sheets-Sheet 1 Inventor LOYD E. H\\ \.s,

By 9mm MM Attorneys March 12, 1940. E. HILLS SAFETY DEVICE FOR GENERATORS Filed July 11, 1939 2 Sheets-Sheet 2 lnveni or LOYD E. HILLS,

. v By waaz izw A iiomeys Patented Mar. 12, 1940 UNITED STATES PATENT OFFICE 3 Claims.

This invention relates to a safety device for generators, the general object of the invention being to provide means for breaking the circuit of the generator if the brushes become too short which would result in burning out of the armature and field coils and also to break the circuit if the generator starts overheating for any reason.

This invention also consists in certain other features of I construction and in the combination and arrangement of the several parts who hereinafter fully described, illustrated in the accompanying drawings and specifically pointed out in the appended claims.

In describing the invention in detail, reference will be had to the accompanying drawings wherein like characters denote like or corresponding parts throughout the several views, and in which:

\ Figure 1 is an end view with parts in section of the generator supplied with the invention.

Figure 2 is a fragmentary top plan view of Figure 1.

Figure 3 is a section on the line 3-3 of Figare 2.

Figure 4 is a section on the line 44 of Figure 3.

Figure 5 is a view of the parts of the invention separated.

In these views the letter A indicates a part of the generator casing, the letter B a portion of the armature and the letter C indicates a brush carried by the supporting member D, these parts being of the usual or any designed construction. In carrying out my invention I provide a bracket l which is connected to a portion 01' the housing A by the screws 2 with a part of the bracket extending into the housing adjacent the opening A of the housing. An enlarged part 3 of a spring steel blade 4 rests on said part I of the bracket and a block 5 of non-conductive material rests on the base part 3 while a thermal blade 6 has an end portion resting on the block 5 and a second block I of non-conductive material rests on the end of the blade 6, all the parts being connected together "and to the portion I of the bracket by the rivets 8 which pass through the pairs of holes in the parts. Sleeves 9 of nonconductive material surround the rivets B where said rivets pass through the blade 6 so as to insulate the blade 6 and said rivets. This blade 6 50 is formed of two strips or different kinds of metal, such as one strip being formed of brass and the other steel so that the strips will bend when subjected to heat and this bending of the strips or blade 8 will cause it to move away from the spring blade 4 so that the contact point l0 formed on the free end of the blade 6 will move out of engagement with the spring blade 4 and thus break the circuit to the parts it the generator becomes overheated.

Also the circuit will be broken by separation of the blades 4 and 6 if the brush C should become unduly worn for when this occurs an angle member ll attached to the brush supporting member D will engage the extended part of the blade 4 and thus separate the blade from the blade 6 and thus break the circuit. It will be seen that the blade 4 is longer than the blade 6 so that the member II will contact the blade 4 without contacting the blade 6 when the brush becomes short.

Thus it will be seen that the circuit will be broken if the brushes should become too short or the generator should become overheated for any reason, such as by loose connections in the circuit wires.

It is thought from the foregoing description that the advantages and novel features of the invention will be readily apparent.

It is to be understood that changes may be made in the construction and in the combination and arrangement of the several parts provided that such changes fall within the scope of the appended claims.

Having described the invention, what is claimed as new is:

1. A safety device for a generator comprising a switch located in the generator circuit, said switch including a pair of spring members normally in engagement with each other to close the circuit and a projection on a brush carrier for separating the two members to break the circuit if the brush should become too short.

2. A safety device for a generator comprising a switch located in the generator circuit, means for opening the switch it a brush becomes too short and means for opening said switch ii the generator should become overheated.

3. A safety device for a generator comprising a switch located in the generator circuit, said switch including a spring steel blade, a thermal blade, means for insulating the two blades from each other, a projection on the thermal blade normally engaging the steel blade, a projection on a brush carrier for separating the two blades it the brush should become too short and the thermal blade moving away from the steel blade when the generator overheats.

LOYD E. HILLS. 

